The instant invention relates generally to surveying, and more particularly to an apparatus for use in vertical projection surveying.
Vertical projection surveying is a fairly recent surveying technique whereby one surveyor fires a magnesium tracer bullet vertically into the air, which bullet makes a visible firey trail that may be sighted upon by a second surveyor using a conventional surveyor's transit or the more sophisticated theodolite. The technique is particularly useful where the surveyor is working in an area that is predominately hilly, or otherwise covered by visual obstacles to the horizontal line of sight.
In order to ensure accuracy when using the above technique, it is extremely important that the trace left by the magnesium bullet be as nearly vertical as possible. This, of course, is most easily accomplished by maintaining the gun barrel through which the bullet is shot at a vertical position. Maintaining a projectile firing device, and in particular a pistol, in such a vertical position is not without its difficulties. Not only must the weapon be initially set at its most vertical position, but it must be maintained in that status through the cocking and firing of the gun.
The prime advantage of the vertical projection surveying technique over standard surveying techniques is the substantial savings of time realized when working in unfavorable terrain. If the weapon alignment and support apparatus requires an excessive amount of time to set up, the savings in time by using the vertical projection technique will be frustrated. Therefore, it is very important that the alignment and support apparatus be easily and rapidly preparable for firing.